How does the Turtle Excluding Device work?

A Turtle Excluding Device (TED) consists of a large metal frame that is inserted into the base (codend) of a prawn trawl. The metal frame (grid) has a series of vertical bars that are spaced relatively close together (80-120mm). The principle being that anything smaller than the bar spacings will pass through the grid and be retained, while anything larger (eg. Turtles, Rays, Sharks) will be directed by the grid to an opening in the top of the net and excluded. A Turtle Excluding Device (TED) consists of a large metal frame that is inserted into the base (codend) of a prawn trawl. The metal frame (grid) has a series of vertical bars that are spaced relatively close together (80-120mm). The principle being that anything smaller than the bar spacings will pass through the grid and be retained, while anything larger (eg. Turtles, Rays, Sharks) will be directed by the grid to an opening in the top of the net and excluded.